Browsing ELibrary by Author "Dahlen F.A."

Browsing ELibrary by Author "Dahlen F.A."

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  • FRECHET KERNELS FOR BODY-WAVE AMPLITUDES 
    Dahlen F.A.; Baig A.M. (2002)
    We derive a 3D Frechet sensitivity kernel relating the rms amplitude of a far-field, broad-band body-wave pulse to laterally heterogeneous seismic slowness variations within the earth. Unlike the 'banana-doughnut' sensitivity ...
  • GLOBAL P AND PP TRAVELTIME TOMOGRAPHY: RAYS VERSUS WAVES 
    Montelli R.; Nolet G.; Masters G.; Dahlen F.A.; Hung S.H. (2004)
    This paper presents a comparison of ray-theoretical and finite-frequency traveltime tomography for compressional waves. Our data set consists of 86 405 long-period P and PP-P traveltimes measured by cross-correlation. The ...
  • RESOLUTION LIMIT OF TRAVELTIME TOMOGRAPHY 
    Dahlen F.A. (2004)
    We derive an explicit formula relating a recovered 3-D seismic slowness image to the actual seismic slowness under the assumption that a tomographically complete collection of finite-frequency traveltime shifts is inverted ...
  • STATISTICS OF TRAVELTIMES AND AMPLITUDES IN RANDOM MEDIA 
    Baig A.M.; Dahlen F.A. (2004)
    In this study, we build on the results of the study of 3-D wave propagation in weakly heterogeneous media conducted by Baig et al. We measure traveltimes and amplitudes from 'ground-truth' seismograms, computed using a ...
  • THREE-DIMENSIONAL SENSITIVITY KERNELS FOR SURFACE WAVE OBSERVABLES 
    Zhou Y.; Dahlen F.A.; Nolet G. (2004)
    We calculate three dimensional (3-D) sensitivity kernels for fundamental-mode surface wave observables based on the single-scattering (Born) approximation. The sensitivity kernels for measured phases, amplitudes and arrival ...
  • TRAVELTIMES OF WAVES IN THREE-DIMENSIONAL RANDOM MEDIA 
    Baig A.M.; Dahlen F.A.; Hung S.H. (2003)
    We present the results of a comprehensive numerical study of 3-D acoustic wave propagation in weakly heterogeneous random media. Finite-frequency traveltimes are measured by cross-correlation of a large suite of synthetic ...
  • WAVEFRONT HEALING: A BANANA-DOUGHNUT PERSPECTIVE 
    Hung S.H.; Dahlen F.A.; Nolet G. (2001)
    Wavefront healing is a ubiquitous diffraction phenomenon that affects cross-correlation traveltime measurements, whenever the scale of the 3-D variations in wave speed is comparable to the characteristic wavelength of the ...